The present invention relates to a continuously variable transmission means for transmitting torque from a driving pulley to a driven pulley, both the driving and driven pulleys having contact surfaces whose cross-sections are V-shaped. More particularly, the present invention relates to improvements in the continuously variable transmission means which increases the range of potential transmission ratios and thereby decreases the fuel consumption rate, and which increases the space in a passenger compartment by making the continuously variable transmission compact in size.
A known technique for coupling an engine with driving wheels utilizes a manual transmission which results in the transmission ratios being influenced by a selected position on a gear shift lever. However, an operator cannot always select an optimum position on the gear shift lever for a maximum conservation of fuel. In order to attain the maximum conservation of fuel, a continuously variable transmission has been proposed.
The continuously variable transmission (hereinafter referred to as CVT) has a V-belt extending between a driving pulley and a driven pulley, and the driving and driven pulleys are connected respectively to input and output shafts of the CVT. Further, the continuously variable transmission includes a predetermined number of metallic hoops, and V-shaped block members which are slidably mounted on the metallic hoops. The V-shaped block members are linked together and extend around the total circumference of the hoops. The driving force from the driving pulley is then transmitted to the driven pulley by a movement of the V-shaped block members. Accordingly, the transmission ratio of the CVT can be changed by varying the size of a V-shaped opening of at least one of the driving and driven pulleys.
However, the transmission ratio of a conventional CVT cannot be of a wide range because of the strength and durability of the V-belt. Accordingly, the conventional CVT cannot achieve a maximum conservation of fuel.